Deck 20: Cooling System Theory

Question 1

20)There is a passage (either a hose or a designed-in passage) that allows the coolant to circulate when the coolant is cold and the thermostat is closed. This is called a(n) ____________________.

Answer 1

thermostat bypass

Question 2

2)All automotive coolants are glycol based.

Answer 2

True

Question 3

4)A constant pressure cap has no spring on the vacuum valve.

Answer 3

False

Question 4

14)Which of the following is LEAST-Likely to help control cavitation?

A) Good antifreeze
B) Good pressure cap
C) Spark plugs
D) Tight connections

Question 5

13)The part that is MOST-Likely to draw air through the radiator when the vehicle is not moving fast enough to provide enough air circulation is the:

A) fan
B) sending unit
C) clutch
D) exhaust port

Question 6

9)If a car has a(n) ____ fuel system, that system will not operate until its sensors have all reached a predetermined operating temperature.

A) cross-flow
B) preignition
C) open loop
D) computer feedback

Question 7

3)Each pound of pressure on the coolant raises its boiling point by about 3°F.

Question 8

6)Technician A says that coolant is a 50/50 mixture of antifreeze and water. Technician B says the terms coolant and antifreeze are used interchangeably by their manufacturers.Who is correct?

A) A only
B) B only
C) Both A and B
D) Neither A nor B

Question 9

1)Coolant exits from the bottom of the radiator after it is cooled.

Question 10

8)The ____ is usually located where the coolant leaves the top of the block, just below the upper radiator hose.

A) thermostat
B) exhaust port
C) vacuum valve
D) fan clutch

Question 11

7)Which of the following is LEAST-Likely to occur?

A) Pure ethylene glycol freezing at 15⁰F.
B) Pure ethylene glycol boiling at 330⁰F.
C) Factory radiator fill being about 50% water and 50% coolant.
D) A 70% concentration of ethylene glycol freezing at -85⁰F.

Question 12

15)All of the following statements are true EXCEPT:

A) the disadvantage of a belt-driven fan is that at higher speeds, when the fan is no longer required, it can rob the engine of horsepower.
B) a flex fan has blades with a flexible trailing edge and a rigid leading edge.
C) fan blades are made of aluminum, flexible plastic, or steel.
D) a fan clutch increases horsepower requirements.

Question 13

11)While discussing thermostats, Technician A says that the installation of a lower temperature rating thermostat will result in a cooler running engine. Technician B says that it will simply result in the engine operating temperature being lower during cooler weather. Who is correct?

A) A only
B) B only
C) Both A and B
D) Neither A nor B

Question 14

19)There are two types of wax pellet thermostats commonly used in pressurized cooling systems: the diaphragm and the ____________________ actuator.

Question 15

5)Blowby, which is exhaust gas that escapes past the rings during combustion, increases when the engine is hot.

Question 16

17)A car with an automatic transmission usually has a(n) ____________________ in the radiator.

Question 17

12)The MOST-Likely indicator of a slow rise in temperature or a fast rise due to a stuck-closed thermostat is the:

A) fan clutch
B) heater core
C) sending unit
D) exhaust port

Question 18

16)Centrifugal pumps are ____________________, which means that their output changes with speed.

Question 19

10)All of the following statements are true EXCEPT:

A) sludge in the oil will increase if the engine is running at too cold a temperature for too long.
B) sludge is a mixture of moisture, by-products of combustion, and water.
C) high emissions and poor fuel economy result when an engine does not reach operating temperature.
D) when an engine is warm, the thermostat is always open fully.

Question 20

18)The ____________________ thermostats used in automobiles have an expansive wax compound that expands at a predictable rate to open the valve in the thermostat.

Question 21

24)Provide three reasons why the thermostat should allow the coolant to quickly reach and maintain a high enough temperature.

Question 22

23)Why are cooling systems pressurized?

Question 23

25)What is the purpose of the radiator shroud?

Question 24

22)Pure water has 1.4 times the heat-carrying ability of pure ethylene glycol, so water would be the best coolant to use if the only consideration in selection of a coolant was its ability to carry off heat. What are its other limitations?

Question 25

21)What are the components of a liquid cooling system?